LECTIN-BINDING DISTINGUISHES BETWEEN NEUROENDOCRINE AND NEURONAL DERIVATIVES OF THE SYMPATHOADRENAL NEURAL CREST

Lectin cytochemistry was used to identify surface epitopes selectively expressed by chromaffin cell chemoreceptors (glomus cells) in the rat carotid body. Unexpectedly, these studies revealed that binding sites for peanut agglutinin (PNA; Arachis hypogea) were highly expressed by all neuroendocrine derivatives of the sympathoadrenal neural crest, i ncluding glomus cells, small, intensely fluorescent cells, and adrenal chromaffin cells in situ. In contrast, principal sympathetic neurons did not express PNA receptors. PNA binding was inhibited by 2% galacto se. To determine whether expression of PNA receptors was selectively i nduced by neuroendocrine differentiation of sympathoadrenal precursors , we compared PNA labeling of embryonic sympathoblasts in the presence of either nerve growth factor (NGF) or the synthetic glucocorticoid d examethasone (DEX). DEX-treated cells, which expressed several neuroen docrine traits, bound PNA, whereas NGF-treated neuronal derivatives di d not. In addition, to examine whether expression of existing PNA rece ptors was down-regulated by neuronal differentiation of chromaffin cel ls, we compared labeling of PC12 cells, which normally bind PNA, in th e presence and absence of NGF. Although PC12 cells acquired characteri stic neuronal morphologies in the presence of NGF, they did not lose P NA labeling, even after 8 days of NGF treatment. These findings indica te that neuronal and neuroendocrine derivatives of the sympathoadrenal lineage can be distinguished by differential expression of carbohydra te epitopes and suggest that PNA receptors are induced by neuroendocri ne differentiation. (C) 1995 John Wiley and Sons, Inc.